The invention concerns a universal folding bicycle.
Currently known types of folding bicycles are designed in a way that enables their folding into a pack with the size corresponding to the height of the bicycle or smaller.
Bicycle folding to the size of its construction is described in WO 97/10141. It is a common type of men""s bicycle. It is folded by rotating the back wheel with the back fork consisting of the chain support together with the central part of the bicycle toward the front wheel. The seat is swung backwards while the handlebars and pedals remain in their original positions. The folding is time consuming, requires tools and the folded bicycle is of an unpractical size.
A common men""s bike with common-type wheels is described in U.S. Pat. No. 5,125,678. Its design enables fairly quick folding by removing both wheels, disconnecting the back fork and swinging the seat support forwards to the seat tube. Folding of this type of bicycle requires tools. Its size is inconvenient and the design makes it impossible to meet the necessary ergonomical requirements.
The bicycle according to U.S. Pat. No.4,895,386 can be folded to a pack with the height of its construction. Its front wheel in the fork with the head assembly in the front tube, the handlebar attachment and the handlebars constitute one unit. The seat with the stem and the seat tube form the second unit. There are two diagonal joining parts between the handlebar assembly and the seat tube, which are attached by two alternating pins to the front and back units. The central assembly with pedals and back wheel is attached to the lower joining part. The bicycle is folded by rotating the joining parts at the pins. In this step the bicycle is shortened so that the back part will align to the front part with the handlebars. The pedals and the handlebars are not folded; they remain in the original width. The disadvantages of this design are the small diameter of wheels, the open chain, and a comparatively large size after folding.
A bicycle, which can be folded into a smaller size, is described in U.S. Pat. No. 5,205,573. It is described as a common men""s bike with wheels of normal size. Its folding is based on a back fork that can be divided at the place where the seat support attaches to the chain support. After removing both wheels, the back fork is divided and the seat support is swung forward to the seat tube around a pin located under the seat. The chain support is swung forward to the front fork around a central pin. Rotating the handlebars 90 degrees completes the folding. Even if it is possible to fold it into a comparatively small size, the procedure is time consuming and requires experience. Tools are necessary. The bicycle design has limited variability. These are the reasons that make this design useless for the common customer.
U.S. Pat. No. 4,634,138 describes a bicycle that has a frame, a prolonged handlebar attachment and a prolonged seat stem with a circular profile. The wheels have small diameters. The whole design makes the impression of a scooter with pedals and handlebars. Folding of this bicycle requires tools, folding of the pedals is dangerous, the driving chain is open, and the design variability is limited.
The bicycle according to U.S. Pat. No. 4,598,923 can be folded to the size of a suitcase. This bicycle has wheels with small diameters. Its folding includes sliding the front wheel into the hollow part of the frame after releasing the accessory pins and rotating the front wheel backwards. The back wheel is slid into the second part of the frame after releasing the accessory pins and rotating the back wheel forwards. The handlebars are folded to the back after releasing the pins on the handlebar attachment. The hollow parts of the frame and the prolonged hollow part of the seat column will create a suitcase by folding them one upon another. The pedals are removed and placed into this suitcase. The disadvantage is that the bicycle wheels have a small diameter and the resulting rolling resistance is too great for a rough terrain. The construction itself has sharp edges, which cause a high risk of injury.
The folding bicycle with wheel springing is described by DE 4313832. Its principle is that it has a rotary embedded swinging lever of back wheel which is spring-loaded against the main frame. The lever can be rotated forwardly. The folding mechanism of front wheel swinging lever serves to the front wheel placing. The size of this folded bicycle does not provide the travel comfort.
The principal disadvantages of the bicycles described above are: small diameters of wheels, open chain, comparatively large size of the folded bicycle, time and expertise requirements when folding, necessity to use tools, low stability of the bicycles, and the lack of springing of wheels and seat.
The universal folding bicycle eliminates the disadvantages of the current designs. It consists of a frame, handlebars, wheels, a seat, and a central assembly with pedals and cranks. The front swing arm with the front wheel is attached to the front arm connected to the head assembly. Adjustable handlebars are attached to the head assembly by the means of a rotary joint, a telescopic handlebar rod or a handlebar attachment. The back wheel is attached to the back swing arm. The back swing arm is connected to the central assembly mounted on the frame that includes pedals with cranks. The seat on a telescopic stem is mounted on the back part of the frame or on the front part of the frame using a pin. The front arm and the front swing arm are interconnected by the front joint or by the telescopic springing of the front wheel or by the front wheel springing. The back swing arm is connected to the frame end by the back wheel telescopic springing or by the back wheel springing. The front wheel is attached to the front swing arm by the means of a unilateral free bearing. The back wheel is attached in the same way to the back swing arm which can be equipped by an accessory arm. The front wheel telescopic springing or the front wheel springing, the rotary joint, the telescopic springing of the front wheel or the front wheel springing, the handlebar axis and the cranks with pedals are all equipped by quick releases.
The seat can be placed into the seat swing arm. It may be equipped by a telescopic seat springing or by a seat arm springing. The telescopic seat springing is mounted on the end of the frame and the seat arm springing is mounted on the central part of the frame.
The height of handlebars can be adjusted by a telescopic handlebar rod in the range of 600 to 1100 mm from the ground and to the distance of 290 to 620 mm from the seat in the horizontal direction.
The distance of frame at the traverse part from the ground can be 150 to 780 mm. The seat can be adjusted in the range of 70 to 150 mm in the anterior-posterior horizontal direction, and 500 to 1100 mm from the ground in the vertical direction. There may be a springing from 55 to 125 mm from the ground.
The handlebar axis permits to limit the handlebar positioning and, subsequently, to stabilize it in a desired position.
The front and back wheels may have a springing from 55 to 210 mm and the steering angle may range from 65 to 80 degrees.
The axle base of the front and back wheel may range from 600 to 1210 mm.
Folding of the bicycle is done in the following way: After releasing the handlebar quick release the handlebars are rotated 90 degrees to the vertical position. The quick release of the rotary joint is released and the handlebars are swung upwards in mountain bikes or backwards in all other bicycle types. Then the front wheel telescopic springing quick release or the front wheel springing quick release is released and the front swing arm with the front wheel, fender, and front wheel telescopic springing or front wheel springing are swung to the centre of the frame. The seat is swung to the centre as well after sliding out of the telescopic stem or the telescopic stem located in the seat swing arm and equipped by the telescopic seat springing or by the seat arm springing.
The back wheel together with the back swing arm optionally equipped by the accessory arm is swung to the centre of the frame after releasing the quick release.
The pedals with cranks located 260 to 350 mm from the ground are removed after releasing their quick releases. Folding of the bicycle does not require strict adherence to the described procedure. We can begin to fold any part of the construction. Reversing the described steps does unfolding.
The folded bicycle is a square with a size equal to the diameter of wheels, or wheels with fenders. The bicycle can be folded without any tools.
The bicycle described in the invention has a complete springing of its both wheels, seat, and handlebars. It permits to vary positions of all parts that are important for the ergonomy and construction, including the distance of the central assembly from the ground, the steering angle, the front wheel track length, the axle base, and the handlebar and seat positions. Therefore, it allows the production of functionally diverse bicycle types ranging from bikes for children, ladies bikes and sport road bikes to mountain bikes. Ladies bicycles are safe, with stable steering and their design parameters permit a comfortable ride even on a boulder pavement of historical centres. There are alternate gears located in the back swing arm that permit ride to a slope and in a rough terrain.
City bikes have a frame placed low above the ground so that it is comfortable to mount and to descend. That is why it is suitable for riding for sport, fun, to school, work and shopping, in and outside of towns.
Mountain bikes are intended for a sport rides on and off road. It can be adjusted perfectly to the weight and height requirements of adults.
Road bikes are intended mainly for sports on reinforced roads for demanding riders. It is possible to adjust the handlebars to a lower position enabling fast racing-style ride or to an upper position for a recreational sport ride on narrow racing tires. It permits a fast and comfortable ride with little rolling resistance. The seat with springing enables to increase the comfort when riding on paved roads.
Different variants of city, sport or mountain bikes for children can be used for the same purposes as the corresponding bicycle types for adults. They, too, permit variability of positions of parts important for ergonomy and construction.
Another advantage of the invention is that it enables production of bicycles with wheel diameters suitable for individual bicycle types. Its size after folding corresponds to a square with sides equal to the diameter of wheels, or wheels with fenders. It can be folded without any tools. It can be folded to the size of a suitcase that permits simple transport as a personal luggage by car, bus, train, airplane, boat, or in an elevator. Folding of the bicycle does not require any expertise and the folding time is not more than 2 minutes.